The present invention relates generally to exoskeletons, and more particularly, to trunk supporting exoskeletons to reduce muscle forces in a user's back.
In general, back support devices which are configured to assist a person in bending, lifting and/or standing upright are known in the art. U.S. Pat. No. 6,436,065, U.S. Pat. No. 5,951,591, U.S. Pat. No. 5,176,622, and U.S. Pat. No. 7,744,552. U.S. Pat. No. 1,409,326 and U.S. Pat. No. 4,829,989 describe devices where moment is created during a bend to counteract the moments from a person's trunk gravity weight. These systems utilize a passive, spring resistance to create a torque between the wearer's torso and legs. By creating a restorative moment at the hip, the probability of injury of the L5/S1 area of the spine is greatly reduced. Once the angle between torso and leg reaches a predetermined angle during stooping, squatting, or walking, the devices provide resistance; however none of the devices differentiate between walking and bending or sitting and bending. This means the user cannot walk comfortably using these passive devices since the user's legs must push against the devices during walking. Similarly the user cannot sit comfortably using these passive devices since the user's legs must push against the devices during sitting. This is uncomfortable and hazardous, preventing the user from moving around unrestricted, and is the most important reason to avoid the use of these systems in various industrial settings.